b) A regular tetrahedron (i.e. made up of four equilateral triangles) with side lengths of 0.5 m forms an enclosure where all surfaces behave as black- surfaces. If the base of the enclosure is held at 300 K while two of the sides are maintained at 500 K, and the remaining side is held at 400 K, calculate the rate of heat transfer to or away from the base, assuming convection is negligible. (The Stefan-Boltzmann constant is σ = 5.67 x √3 10-8 W m² K-4 and the area of an equilateral triangle is A = 1² where / is the length of one of the sides of the triangle) 4 500 K 400 K 0.5 m 500 K 300 K